Strength of Composite Beams at Web Openings

A model for the strength of steel-concrete composite beams with unreinforced, rectangular web openings is presented. The model includes the contribution of the concrete slab to shear strength, as well as flexural strength. Steel is represented as an elasto-plastic material with no strain hardening. Openings may be concentric or eccentric with respect to the steel section. Comparisons are made with test results. The model provides realistic, and generally conservative, predictions of the strength for the test beams. The contribution of the concrete slab to shear strength at an opening must be included to obtain a realistic model.